forEach

Applies a procedure to all container elements. Returns the argument (any
subclass of DoubleProcedure. This lets the caller to call methods of the argument
by chaining the call (even if the argument is an anonymous type) to retrieve computed values,
for example (IntContainer):

iterator

Returns an iterator to a cursor traversing the collection. The order of traversal
is not defined. More than one cursor may be active at a time. The behavior of
iterators is undefined if structural changes are made to the underlying collection.

The iterator is implemented as a
cursor and it returns the same cursor instance on every call to
Iterator.next() (to avoid boxing of primitive types). To read the current
list's value (or index in the list) use the cursor's public fields. An example is
shown below.

size

Return the current number of elements in this container. The time for calculating
the container's size may take O(n) time, although implementing classes
should try to maintain the current size and return in constant time.